Fast evacuation valve



J. L. GRATZMULLER 3,419,030

FAST EVACUATION VALVE Filed Nov. 8, 1965 shet of s Dec. 31, 1968 J.GRATZMULLER 3,419,030

FAST EVACUATION VALVE Filed Nov. 8, 1965 Sheet 2 of 3 J. L. GRATZMULLERFAST EVACUATION VALVE Filed Nov. 8, 1965 Sheet al f 1 as 7 2 A w A00 452 25' 76 I W ?i Unite States Claims. 61. 137-102 ABSTRACT OF THEDISCLOSURE A fast evacuation valve for a hydraulic control jack whereina chamber interposed in the jack feed conduit is sub-divided by a pistoninto first and second compartments connected to the pressure fluid inletconduit and jack. An evacuation conduit communicates with the secondcompartment and an evacuation valve connected to the piston controls itsorifice. The piston has passage means permitting communication betweenthe compartments controlled by a non-return valve allowing fluid flowonly from the supply to the jack. This latter valve is a ring concentricwith the piston slidable on the exterior of a portion between the pistonhead and evacuation valve.

This invention relates to improvements to fast evacuation valves forhydraulic jacks and, inter alia, hydraulic jacks for the control ofcircuit breakers.

A valve according to the invention, which will hereinafter be referredto as a fast evacuation device, is an automatic three-way valve adaptedto provide selectively communication between a jack, or more generallyany hydraulic load, and a pressure fluid source, or between such jackand a large-section evacuation pipe, with this second arrangementoccurring automatically as soon as the pressure in the jack is greaterthan that in the feed pipe connecting the source to the jack.

A valve of this type therefore enables the jack evacuation to becontrolled simply by decompression of the feed pipe (for example in thecase of a single-acting jack adapted to make a circuit breaker againstthe action of elastic means adapted to break the circuit breaker) oralternatively when the pressure in the jack is higher than in the feedpipe (for example in the case of a doubleacting jack which provides formake and break of the circuit breaker upon its direction of operation).

In either case a valve of this type enables the liquid to be evacuatedwithout passing it through the feed pipe, which is generally very longand of relatively small section, since this would have the disadvantageof braking evacuation, and the evacuated liquid flows through a pipereserved solely for this purpose and which can therefore be both shortand large. In circuit breaker control systems, in which operations haveto be very fast, particularly on break, it is very advantageous for thevalve or valves to be disposed in the immediate vicinity of the jackthat they control.

A valve of this type has already been described in my US. Patent No.2,888,909.

The present invention relates to certain improvements giving a simplerand hence cheaper construction than those of prior art valves, and interalia because of the elimination of any internal precision machining orany male or female screwthreading of the movable closure elements of thevalve. Also, these new features give a freer choice for the sections ofthe various passages whereby the hydraulic fluid flows through thevalve. Finally, a new type of construction enables a single valve bodyto be fitted to different hydraulic circuits as a result of the specificshape of the valve body and the fact that 3,419,030. Patented Dec. 31,1968 it is adapted to receive various types of connecting members forthe hydraulic circuit.

According to the invention, a fast evacuation valve for a hydraulic jackcomprises a chamber interposed in the jack feed conduit and subdivided,by a piston sliding in a bore in the valve body, into a firstcompartment connected to the pressure fluid inlet conduit and a secondcompartment connected to the jack; a large-section evacuation conduitcommunicating with the second compartment and with its orificecontrolled by an instantaneously opening evacuation valve which isconnected to the piston; and at least one passage formed in the pistonso that the two compartments can communicate with one another, with thepassage being controlled by a non-return valve which allows fiuid toflow only from the supply to the jack and which is in the form of a ringconcentric with the piston and slidable on the outside of anintermediate cylindrical portion between the head of the piston and theevacuation valve.

According to one embodiment, the evacuation valve is formed by the freeend of the piston rod, with the rod preferably being an integral part ofthe piston, as is therefore the evacuation valve; the ring which formsthe non-return valve slides around the said piston rod.

In a preferred embodiment, the passage or passages formed in the pistonfor communication between the two compartments lead radially into thesecond compartment on the outer surface of the piston rod and thesliding ring controlling the opening of the passages has surfaces normalto the sliding axis, with such surfaces being subject to the pressuredifference between the first and second compartments, the resultantforces controlling the opening and closure of the valve.

Advantageously, at least one of the valves, the evacuation valve or thenon-return valve, is permanently loaded into the closure position by aspring.

According to one feature, the valve body is of parallelepipedic externalshape, preferably of square section, and connection members are securedin sealing-tight relationship to one or more of the flat surfaces of thevalve body to which the valve conduits lead, with such members enablingthe valve to be connected to the various conduits of the hydrauliccircuit for control.

By this arrangement the connections may be made according to the mostfavorable orientation with a standard valve body and a small number ofdifferent connection members.

The invention will be more readily understood from the followingdetailed description and the accompanying drawings which illustratevarious embodiments of the invention by way of non-limitative example.

FIGURE 1 is an axial section of one embodiment of a fast evacuationdevice according to the invention.

FIGURE 2 is a view partly in elevation and partly in section showing anexample of the use of such a fast evacuation device in a hydrauliccontrol circuit for a circuit breaker.

FIGURE 3 is an axial section of another embodiment of the invention.

FIGURE 4 is a perspective view showing the arrangement of hydraulicconnections according to a variant of the invention.

FIGURE 5 is a view partly in elevation and partly in section of a fastevacuation device according to the invention in combination with ahydraulic jack.

FIGURES 6 and 7 are views partly in elevation and partly in section oftwo variants of hydraulic control jacks for a circuit breaker, withwhich a fast evacuation device according to the invention may becombined.

Referring to FIGS. 1 and 2, a fast evacuation device valve body "2 isformed with a bore 4 which provides a chamber between a pressure oilinlet pipe 6 and a feed pipe 8 to a hydraulic jack 10. The chamber issubdivided 'by a piston 12, which slides in the bore 4, into a firstcompartment 14 connected to the pressure fluid inlet pipe and a secondcompartment 16 connected to the jack 10. An evacuation pipe 18communicates with the compartment 16 and its orifice or seat 20 iscontrolled by an evacuation valve 22 of the instantaneous opening type,which is connected to the piston 12 and which in the example illustratedforms an integral part thereof. A plurality of passages 24 are formed inthe head of piston 12 so that the two compartments 14 and 16 cancommunicate and these passages are controlled by a nonreturn valve whichallows oil to flow only from compartment 14 to compartment 16. Accordingto the invention, the non-return valve is in the form of a ring 26 whichis concentric with the piston and which slides on the outside of anintermediate cylindrical portion, or piston rod 28, between the piston12 and the valve 22.

According toa preferred embodiment, the two valves 22 and 26 arerespectively urged into the closure position by springs 30 and 32respectively. Of course, in the case illustrated in FIG. 1, in which thespring 32 bears against the end of the bore 4, the spring 30 is strongerthan the spring 32.

The operation of the fast evacuation device will be described justbriefly in connection with FIG. 2 which diagrammatically illustrates ahydraulic control system for a circuit breaker as described in my US.Patent No. 2,900,469. In this control system, when the jack receivespressure oil from an oleopneumatic accumulator 36 piston 34 of the jackbrings movable contact 38 of the circuit breaker into the make positionagainst fixed contact 40 and holds it in this position against theaction of break spring 42. The fast evacuation device 2 has been shownas being directly secured to the jack 10.

When control valve 44 is brought into position 44', pressure oil fromthe accumulator acts on the top surface of the piston 12 and firmlyapplies the valve 22 to its seat to shut off the evacuation. Under thepressure effect the ring type valve 26 moves away from the apertures 24against the spring 32 and oil flows into the chamber 16 and then viapipe '8 to the jack 10 in which it pushes the piston 34 back against thespring 42. The circuit breaker is thus in the make position. When thevalve 44 is returned to the position shown in FIG. 2, feed pipe 46expands and the higher pressure in the jack 10 applies the ring typevalve 26 firmly against the passages 24 at the same time as the piston12 is lifted against its spring 30. The evacuation valve 22 thereforeopens instantaneously and the oil contained in the jack 10 is rapidlyevacuated via the large pipe 18 to a tank 48. The circuit breaker cantherefore break at high speed under the effect of its spring 42 withoutthere being any braking as a result of the oil.

Of course, a fast evacuation device of this kind can be used in numeroushydraulic control circuits different from the one diagrammaticallyillustrated and, inter alia, control circuits of the type described inmy US. Patent No. 2,900,960.

The new fast evacuation device according to the invention has numerousadvantages over evacuation valves known heretofore, such advantagesbeing due, more particularly, to the external arrangement of thenon-return valve. None of the moving .parts of the valve has either amale or female screwthread and no precision female bore is required, sothat the cost price is greatly reduced. In the embodiment shown in FIG.1, the only precision machining requirement is concentricity between thebore 4 (which guides the piston 12) and the evacuation orifice 20 (whichacts as the valve seat) to give good closure of the frustoconicalevacuation valve 22. However, it will be apparent from the embodimentshown in FIG. 3 that even this precise machining: can be avoided. Also,the arrangement of the non return valve outside the piston, or moreparticularly outside the piston rod, enables the passages 24 to be givena total section much larger than in prior art evacuation valves inwhich, for a given evacuation aperture section, the section offered tothe passage of the oil to feed the jack is sometimes inadequate.

The preferred embodiment shown in FIG. 3 comprises all the main elementsalready described in connection with FIG. 1 (with the same referencenumerals). One of the variants comprises arranging the passage orifices24' which form the communication between the compartments 14 and 16 tolead radially to the outer surface of the piston rod 28 instead of inparallel relationship to the axis as in FIG. 1. To ensure that thepressures exerted by the pressure oil on the ringtype non-return valve26 produce an axial force thereon, the ring is formed with an innershoulder 48' and is continued in the form of a skirt 50 which givessubstantially sealing-tight sliding of the ring on the rod 28.

The ring type valve return spring 32 can bear against a collar 52 whichis held by a resilient gasket 54 fitted in a groove in the rod 28. Thetwo springs 30 and 32 are thus independent.

These variants give a larger total passage section through the orifices24', Which can be of larger diameter than in the case shown in FIG. 1,and also do away with the need for the oil to have to flow through thecoils of the springs 30 or 32 (as in FIG. 1), thus eliminating anyadverse pressure losses or vibrations.

Another variant is the evacuation valve 22, which is flat, i.e. theco-operating surfaces of the seat 20 and of the evacuation valve areperpendicular to the valve axis. These flat surfaces can be machinedeconomically and yet with precision, and the sealing properties of theevacuation valve no longer depend on perfect concentricity of the bore 4and the evacuation valve seat, so that the valve production isfacilitated.

According to another variant, the evacuation pipe 18' for the valve,which is connected to the axial conduit 18, discharges radially on thevalve side, while the jack feed conduit or conduits 8 are formed inparallel relationship to the axis of the valve and lead into thecompartment 16 whose diameter is larger than that of the bore 4. Thisarrangement enables the fast evacuation device to be fitted directly atthe end of the jack 10 which it is required to control, for example bymeans of a collar 56 held on the evacuation device body by a resilientgasket 58 and secured to the jack by screws 60. A gasket 62 providessealing-tightness between the fast evacuation device and the jack 10.

In circuit breaker hydraulic control installations it is frequentlyadvantageous, as described in my US. Patent No. 2,933,069, to regularizethe rates of liquid flow corresponding to the make and break operationsby throttle means interposed in the pipes or conduits, inter alia withthin-walled calibrated jets disposed as close as possible to the jackswhose speed is to be controlled.

A calibrated jet may advantageously be combined with a fast evacuationdevice according to this invention. A jet 64 can rest on a step 66 onthe piston 12 and be held thereon by the piston return spring 30. Thisarrangement gives a very simple and economic system, enables the jet tobe disposed immediately near the jack, thus minimizing any vibrationsdue to the compressibility of the liquid, and gives a pressure losswhich tends to apply the valve 22' to its seat.

According to a preferred embodiment, the fast evacuation device body 2is given a parallelepipedic external shape of square section (FIG. 4)and connection members 64-66 are fitted to its ends opposite the feedand drain conduits. With just two types of connection members, one withan axial outlet 68 and the other with a side outlet 70, it is possibleto obtain any required direction of the outlet conduits. The connectionmembers are simply secured to the valve body by four screws 72 arrangedin the form of a square and four 90 directions can be chosen for eachconnection member. Of course, a gasket 74 is provided between the valvebody and the connection members (FIG. 5).

The valve conduit 8 or 8' can be connected to the jack via a connectionmember 74, the same as those mentioned hereinbefore, which is secured bymeans of four screws to the fiat side of the valve body (FIG. 4) and canbe directed as required.

Preferably, however, the evacuation device is generally fitted directlyto the jack as shown in FIGS. 3 and 5. In the latter figure, theparallelepipedic body 2 of the fast evacuation device is secured by fourscrews 76 to a base 80 into which cylinder 82 of the jack is screwed. Agasket 62 is provided between the evacuation device body and the base.

Jack piston 84 shown in this figure has a gasket 86 formed by aplurality of rings which are kept compressed by a spring. A gasket ofthis kind has been described, inter alia, in my US. Patent No. 2,847,262and US. continuation-in-part application No. 378,901.

In the jack shown in FIG. 5, in combination with a fast evacuationdevice, the piston rod is guided at the top end of the cylinder 82 by ametal ring 88 provided with a ring gasket 90 which prevents anypenetration of moisture and dust into the space between the calibratedpiston rod and the cylinder 82. This ring gasket also cleans the pistonrod on each operation. However, said space, whose volume varies duringthe make or break operations (in the case in which the jack actuates themoving contact of a circuit breaker), must not be completely sealed andmust be able to evacuate any oil leakages.

To this end, the wall of the cylinder 82 is formed with a respirationaperture 92 which is normally closed by a valve 94 loaded by a spring 96so as to prevent any penetration of moisture, with the valve openingonly in the event of an excess pressure in the said space.

FIGS. 6 and 7 show another two examples of a fast evacuation deviceaccording to the invention combined with hydraulic control jacks for acircuit breaker.

The jacks shown are direct long-stroke jacks of the type described in myFrench Patent No. 1,391,147.

These two figures show fast evacuation devices 2 with a body ofparallelepipedic shape directly secured by screws 76 to the jack base80.

In this variant, oil inlet and evacuation connections 98 and 100 aredirectly screwed into the valve body (as in FIG. 1) without the use oforientable connection members of the kind described in connection withFIGS. 4 and 5.

This invention is not to be confined to any strict conformity to theshowings in the drawings but changes or modifications may be madetherein so long as such changes or modifications mark no materialdeparture from the spirit and scope of the appended claims.

I claim:

1. A fast evacuation valve for a hydraulic jack, and more particularlyfor a hydraulic control jack for a circuit breaker, comprising a valvebody, a jack feed conduit, a pressure fluid inlet conduit, a chamberinterposed in the jack feed conduit, a piston having an integral pistonrod slidable in a bore in the valve body sub-dividing the chamber into afirst compartment permanently connected to the pressure fluid inletconduit and a second compartment connected to the jack, a large-sectionevacuation conduit communicating with the second compartment and havingan orifice, an instantaneously opening evacuation valve formed by theend of the piston rod controlling said orifice, first spring meansurging said evacuation valve to closed position, at least one passageformed in the piston to provide communication between the twocompartments, a non-return valve controlling said passage and allowingfluid to flow only from the supply to the jack, second spring meansurging the non-return valve to closed position, said first spring meansbeing stronger than the second spring means, and said non-return valvebeing defined by a ring concentric with the piston and slidable on saidpiston rod.

2. The valve according to claim 1 wherein the evacuation valve and saidorifice have flat cooperating surfaces perpendicular to the axis ofmovement of the valve.

3. The valve according to claim 1 wherein the piston is provided with abore opening into said first compartment, said piston rod having radialapertures interconnecting the bore in the piston rod and the secondcompartment, and the slidable ring controlling the radial aperturescomprises at least one shoulder on its inner surface so that theresultant of the pressure forces acting on the ring extends in parallelrelationship to its axis and not radially.

4. The valve according to claim 1, comprising a calibrated jet toregularize the rate of flow of the hydraulic fluid, said jet beingprovided in the communication passage of the valve.

5. A fast evacuation valve for a hydraulic jack, and more particularlyfor a hydraulic control jack for a circuit breaker, comprising a valvebody, a jack feed conduit, a pressure fluid inlet conduit, a chamberinterposed in the jack feed conduit, a piston slidable in a bore in thevalve body sub-dividing the chamber into a first compartment connectedto the pressure fluid inlet conduit and a second compartment connectedto the jack, a large-section evacuation conduit communicating with thesecond compartment and having an orifice, an instantaneously openingevacuation valve connected to the piston controlling said orifice, atleast one passage formed in the piston to provide communication betweenthe two compartments, a non-return valve controlling said passage andallowing fluid to flow only from the supply to the jack and saidnon-return valve being defined by a ring concentric with the piston andslidable on the outside of an intermediate cylindrical portion betweenthe head of the piston and the evacuation valve, a calibrated jet toregularize the rate of flow of the hydraulic fluid, said jet beingprovided in the communication passage of the valve and said jet being inthe form of a washer having a calibrated orifice and held against thepiston in register with said passage by a spring which permanently loadsthe piston in the position corresponding to closure of the evacuationvalve.

References Cited UNITED STATES PATENTS 122,544 1/1872 Westinghouse137-102 2,488,949 11/ 1945 Walsh 137-102 XR 2,706,487 4/1955 Wilson137-102 2,888,909 6/ 1959 Gratzmuller 121-38 2,900,960 8/1959Gratzmuller 121-38 2,933,069 4/ 1960 Gratzmuller 121-38 3,042,061 7/1962 Dobrikin 137-102 WILLIAM F. ODEA, Primary Examiner.

WILLIAM H. WRIGHT, Assistant Examiner.

US. Cl. X.R.

